The invention relates generally to the lining of articles. Of particular interest to the invention are a method and arrangement for the lining of ovens such as melting ovens.
A procedure for finishing a melting oven is known wherein the melting oven is provided with a refractory lining using a ramming mass which is sintered in order to convert the same into a unitary mass constituting the lining. Here, a metal form or mold member is utilized to confine the initially particulate ramming mass. The mold member, which is of smaller dimensions than the oven chamber which is to be lined, is inserted into the oven chamber so that a space is defined between the mold member and the inner wall of the chamber. The ramming mass is poured into this space and thereafter sintered.
Three methods have been used heretofore for finishing a melting oven in accordance with a procedure of the type just outlined.
A first method for finishing a melting oven according to a procedure of the type outlined above consists in placing the metal mold member is an oven which has been completed to the point where it is ready to be provided with a lining. The ramming mass is poured in and, with the mold member still in position in the oven, is sintered. As a result of the sintering operation, the particles of the ramming mass cohere and the ramming mass becomes firm. As already mentioned, the metal mold member remains in the oven during the sintering operation. By virtue of this, the mold member is melted. In other words, in order to finish an oven of this type in the manner described, a new metal mold member is required for each finishing or lining operation. Since the costs for a metal mold member of the type utilized are very high, the disadvantage of the method just described is readily apparent.
Another known method for the finishing of a melting oven resides in that a ramming mass of a very precisely determined composition is utilized. After placing the metal mold member in the oven and pouring in the ramming mass as before, the metal mold member is withdrawn from the oven and a binding agent is sprayed onto the inner layer of the ramming mass. In this manner, the ramming mass is hardened to a certain depth. Subsequently, the remainder of the ramming mass is solidified by heating.
In the latter method, the special composition of the ramming mass is intended to permit the withdrawal of the metal mold member from the ramming mass, after this has been poured in, without damage to the ramming mass, which later has as yet undergone no substantial hardening. Although it is true that this method enables the metal mold member to be used as often as desired, it has, however been observed that this method is not entirely satisfactory. Thus, it has been found that, despite the use of a ramming mass having a special composition, the desired result is dependent upon so many factors which cannot be controlled with any degree of certainty, that an economically feasible utilization of this method is not possible.
Still another method has been used in which, again, a metal mold member is placed in the oven and a ramming mass is poured in. Here, after pouring in of the ramming mass, the metal mold member is heated to such an extent that the layer of the ramming mass immediately adjacent the outer wall of the metal mold member is rigidified to a certain extent. Thereafter, the metal mold member is cooled with compressed air and then withdrawn from the oven. Subsequently, sintering of the ramming mass is completed.
In accordance with the last-described method, the metal mold member is also not melted and can thus be reused. However, a disadvantage of this method resides in that the metal mold member is very strongly corroded by virtue of the heating and subsequent cooling thereof so that re-use of the metal mold member is possible only under very limited conditions.
It will be appreciated, therefore, that improvements in the state of the art are desirable.